Articles of interest from the Fairfax County Park Authority

Tag Archives: Hidden Oaks Nature Center

A child attending a birthday party at Hidden Oaks Nature Center discovered this camouflaged fawn hiding under a fallen tree.

“Mommy! Quick. I need a shoebox.”

Parents hear this cry spring and summer. Somebody has found a baby animal.

Before you respond to this plea in your home, take a moment for you and your child to learn about these cute, fuzzy, lovable baby animals. And remember – it’s a wild animal.

Most everyone has found, or knows someone who has found, a baby animal. Children are especially good at locating them, and reasonably so. Kids are curious, low to the ground, outside playing and willing to venture into areas adults would shun. Children have a difficult time understanding that animals naturally do what kids most fear – leave their young alone. The excitement of finding a bunny in tall grass or a helpless young squirrel at the base of a tree is enrapturing, and the urge that follows is irresistible – the baby must be saved! The idea of a new, exciting pet also appeals to children and, likewise, to many adults.

A young Suzanne Holland holds Baby Rabbity.

I have fond childhood memories of Baby Rabbity, a week-old bunny that I pulled from the mouth of a neighbor’s dog. I was thrilled that we couldn’t find the nest and that my parents agreed to let us keep it. I did not have the responsibility of the feedings throughout the night, so I was happier about the new visitor than were my parents. (In hindsight, we exacerbated our foundling’s problems because nestlings are typically fed only twice a day, and cow’s milk is an inappropriate substitute.) Our beagle paid no attention to the guest for about three weeks. Then the howling began. The rabbit’s scent had developed, as did an unfortunate trait of not wanting to be handled by little girls. After it bit a friend, my mother found a home for it with a breeder who had to promise to provide milk for Rabbity since it had never learned to drink water.

Although that rabbit’s chances of survival, if we had left it in the brush, were slim, we were not qualified to raise a young, wild creature effectively to achieve a successful release into its normal habitat. Today, those who live in Northern Virginia are fortunate to have a dedicated group of trained, licensed volunteers who are wildlife rehabilitators. When a young animal has been truly abandoned, injured or is ill, a call to your nearest nature center is a prudent step. We can provide you with the phone number of the nearest wildlife rehabilitator.

Most foundlings are not really abandoned but have been left alone for their own protection. As is the case of our bunny foundling, the young have no scent, whereas the mother does. Rabbits and deer both leave their young in a protected area for most of the day, returning only to feed them. A predator would be unlikely to find a quiet, still creature without scent to assist him. By the time scent is developed, the young should have developed skills for survival.

Allowing wildlife to remain wild is as important for human safety as it is for the wild animal itself. Many federal, state or county ordinances prohibit the harboring of wild “pets.” One reason is that these creatures can carry diseases which are transmittable to humans, including rabies, histoplasmosis, roundworm, salmonellosis and tuberculosis. Grey squirrels, while not common carriers of rabies, are flea infested. Fleas can rapidly spread disease.

Even if the goal is to release the animal back into its habitat at the earliest possible opportunity, caretaking is not advisable. Less than 10 percent of adopted wild animals survive in captivity. Relocating animals also has a low success rate. Rescuing wildlife and providing the care required for a successful release into the wild takes time, patience, training – and the proper permits! Rehabilitators are trained periodically. For information, contact the Wildlife Rescue League at 703-440–0800.

Maybe it’s just a flash of movement. Just past dusk, you notice something out of the corner of your eye as long shadows play dart games with sunlight. Or perhaps the birdseed runs low unusually fast. Sitting on your deck at night, you hear a high-pitched chirp. There may be acorns with meticulously rounded holes cut through the sides scattered along a path. In any of these cases, your backyard may be home to one of the area’s most abundant, least seen, and most charming wildlife neighbors – the southern flying squirrel.

These tree squirrels, Glaucomys volans, are active year-round but are typically unseen. Your best chance to spy one is in late fall through the winter when leaves have renounced their places among the branches. They will be high in the treetops dining on silkworm caterpillars, seeds, maple sap, fungi and fruits. It’s an omnivorous diet that includes bird eggs, carrion and sometimes a small mammal. As the temperature drops, so does their range of comestibles, so they focus on nuts. They’re partial to hickory and hazelnuts. Roosting and nesting boxes can easily lure them within viewing range if supplemented with nuts and mealworms.

So what are these curious creatures? They’re alluring rodents. Our native flying squirrel weighs less than 90 grams, about the same as a half box of mac and cheese or a king size candy bar. They’re less than 10 inches long with a tail less than five inches long. They rate very high on the “cute” factor with large black eyes and a face covered with whiskers. Their fur is a mottled grayish-brown on top and white underneath.

And they have this great gimmick. They can fly. Not flap-fly. They glide. They have something called patagium, stretched skin between the fore and rear paws that can expand. They’re like fuzzy parachutes. High speed photography has shown us that flying squirrels can adjust their skin flaps to turn, gain lift and outmaneuver predators of the nighttime forest, barred owls or great horned owls. The tail serves as rudder and brake while the whiskers, or “vibrasse”, contact the landing surface first, allowing for safe touchdown.

On the move from approximately 30 minutes after dusk until just before dawn, flying squirrels industriously cache nuts in multiple locations. eNature says flying squirrels may store 15,000 nuts, including acorns, for a season.

Preferring the high rent district of an abandoned woodpecker hole, these tiny creatures sometimes may have to build their own miniature “drey,” a squirrel nest made of leaves. Other accommodations could include attics or bird houses. They use multiple nest sites, but winter’s desire for warmth trumps solitude, and many squirrels may den together.

A lack of deep cavities in sturdy branches encourages flying squirrels to use manmade nesting boxes, which look like a long narrow birdhouse. The opening is next to the trunk instead of in the front, because flying squirrels avoid the potential exposure of climbing on the front of the box. If you want to draw them to your yard, add a roosting box downstairs on a lower part of a tree, and fill it nightly with a dozen unsalted roasted peanuts or, for a treat, hazelnuts or mealworms. Remember, the entrance hole needs to be next to the trunk to calm their fears.

Flying squirrels and our everyday grey squirrels are far from kissing cousins. They are more like mortal enemies. So if you want to attract flying squirrels, timing is everything. Feeding must coincide with the hours that grey squirrels have tucked themselves away at night. Try peanut butter inside the roosting box or on the metal flashing surrounding the entrance hole. Avoid putting peanut butter on the tree trunk. That will encourage chewing on the tree bark by all types of squirrels and raccoons.

The best way to be a good neighbor to flying squirrels and other wildlife is to keep one of their top predators away — house cats. Flying squirrels regularly return to earth to get water or nuts and seed. They sometimes fall prey to fox, but more often house cats. Practice backyard habitat basics. Provide a fresh water source, plant native plants for their fruit and nuts and for the helpful insects they attract, leave trees with cavity holes standing when safe, and don’t use insecticides.

Lay out the welcome mat to flying squirrels, and you can usually see guests arrive within a week. By quietly getting closer, you may soon enjoy the thrill of watching them soar in from as far as 100 yards away. These squirrels get used to people quickly and will even stay still long enough for a well-prepared photographer.

An easy way to see flying squirrels and determine if you have them already in your yard is to attend a program on flying squirrels at a park nature center. Since 2008, flying squirrels have been kindly showing up Hidden Oaks Nature Center on schedule to delight visitors. Eagle Scouts have built and mounted roosting and nesting boxes, and the plans are available on request.

Longing to enjoy the beauty of spring but don’t have the time or energy to hike out and find the elusive native wildflower spring blossoms? Walk one hundred feet of sidewalk from our driveway to the front door and enjoy a burst of spring color from over a dozen native plants!

Blooming today are Virginia bluebells, toad trillium, squirrel’s corn, violets, golden ragwort, spring beauties and the unusual Dutchmen’s breeches. Also marvel at the redbud tree with the bright pink blossoms popping right off the limbs and the last of the tiny yellow flowers of the spicebush. Wander a short woodchip trail to see more flowers plus mayapples and ferns.

Jacob’s Ladder will be blooming soon, so head over to the nature center to see these spring ephemerals before the shade of the trees wraps up one of nature’s glorious shows. If you have a few minutes more, head over to the pond around the other side of the nature center. Thousands of yellow-spotted salamander eggs are catching some rays and wood frogs are munching on plants in their tadpole stage. Any day now the male toads will arrive, trilling for their mates and strings of toads eggs will be added to this busy little pond.

His nickname among some of the staff was Darling. An odd name, perhaps, for a snake, but it did reflect a kind of fondness for him.

We don’t give our exhibit animals actual names because they aren’t pets. We’re naturalists, not purveyors of anthropomorphism. We don’t want to bestow human qualities on exhibit animals because our job is to interpret nature, not humanize it.

But after 20 years with an animal, some kind of relationship forms. And so we noted on March 6, 2013, the passing of the eastern rat snake that spent the past two decades at Hidden Oaks Nature Center in Annandale.

Hidden Oaks Assistant Manager Suzanne Holland tells the story:

We were given the snake in 1993 while it was still an egg along with a few others after a homeowner found a clutch in his mulch pile. Rarely do reptile eggs that are moved survive, for unlike bird eggs, the yolk is unstable in these eggs. But he made it. During the snake’s first year of life, he sported the blotchy gray and black pattern of a juvenile eastern rat snake. These snakes are notoriously aggressive as juveniles, and he bit the animal care staff at every opportunity. Being non-venomous and small, he left only pinprick punctures, and he was not a danger to anyone. As he matured, he got used to being handled and thrived as an exhibit animal. He was often used in school programs and for outreach. His laminated skin, six feet long and shed more than three years ago, is an awe-inspiring sight. Students and parents alike are stunned to learn that he was closer to seven feet long. Since snakes don’t stretch out the way mammals like to, his true size was often underestimated.

If you’ve been to Hidden Oaks sometime over the past 20 years, you’ve probably seen the snake. Although he will be missed, he also will be replaced. Hidden Oaks will remember him only with a photo, one that Holland calls “his glamour shot,” as the eastern rat snake finished a meal of mouse.

A marvel of nature roams the woods, usually silent but for a raucous spring display. Wood frogs, Rana sylvatica, which spent the winter frozen under leaves, have started their annual concert tour of Fairfax County Park Authority forests.

Wood frogs are the only frogs that can live north of the Arctic Circle. They can withstand more than half of their body water freezing without damaging their cells because urea accumulates in their tissues and glucose forms in their livers. This is natural antifreeze that also enables the frog’s heart to cease beating and the lungs to stop breathing. The wood frogs, buried under woodland leaves instead of overwintering on muddy pond bottoms like most other frogs, can thaw and refreeze throughout the winter without harm.

Last month, males began racing to their local hangouts — ponds and vernal pools — emitting a noisy, bizarre call that resembles a laughing cartoon duck to entice the females to join them. Wood frogs are not the first amphibians you’ll hear heralding spring in our area. That honor goes to the smaller spring peeper. However, wood frogs, brown with a black eye mask and about three inches in length, are more easily seen and heard.

Wood frogs’ camouflage help them blend into their surroundings.

Wood frogs commonly choose vernal pools as a breeding area because these temporary bodies of water do not host fish and turtles, which are natural predators of the frog eggs and tadpoles. At Hidden Oaks Nature Center is a pond that is purposely kept free of fish and bullfrogs to support breeding amphibians. Each year we welcome wood frogs, followed by American toads and then spotted salamanders, to breed.

Wood frogs visit the pond to seek out a mate.

Even with a suitable site, there are difficulties finding love in the pond. During the breeding frenzy, males may mistake a male for a female or may drown the female, especially problematic for the first females to arrive on the scene. Males emit a loud croak to warn off the advances of other confused males. When the females – the silent sex – arrive, the males clasp them with their forearms in an embrace called “amplexus”. The smaller male holds onto the female until she deposits her eggs (over 1,000 of them), which usually attach to submerged plants or other egg masses.

Female wood frogs can lay over 1,000 eggs.

After just a couple of days, breeding is complete and the parent frogs return to the forest to hunt for insects, worms and arachnids. Tucked back into the forest floor, the adults ignore their offspring and leave behind standing pools soon to be filled with hundreds of tadpoles.

Meanwhile, the egg masses develop algae which provide more oxygen for the young. The eggs in the center of the mass, warmed by the other eggs, develop faster. The warmer the water gets, the speedier the development. Within weeks, the tadpoles wriggle out of their jelly-like egg masses and develop rapidly, growing their back legs first. They scrape algae and decaying plants with a beak-like mouth. As they mature, they are omnivorous and will eat other amphibian eggs and larvae, including other wood frog larvae. Overcrowding and low temperatures can be deadly at this stage, and many tadpoles become meals for another frog, a turtle, a salamander, beetles, leeches or even an owl. Ever full of surprises, the wood frog tadpoles actually seem to recognize siblings and congregate with them. Nevertheless, the sisters and brothers are together for only a few weeks.

By June, the froglets leave the pond, unaware that they’re joining their parents in the nearby woods. About one-fifth scatter, unfortunately finding their way onto roads and, without the important skill set developed in the video game Frogger, they get squished, providing food for birds, raccoons and opossums. By the time they settle into their homes in the woods, they are virtually indistinguishable from the leaf litter. They will spend the summer finding food and trying to avoid snakes, raccoons, skunks, coyotes, foxes and birds. Wood frogs in turn hunt for snails, worms, beetles, spiders, slugs and other arthropods. They are adept hunters that can ambush their prey. Staying silent until the end of winter, wood frogs’ cacophonous duck-like chatter will again pierce the March air next year.

You’ll find wood frogs from the southern Appalachians into the boreal forests of Canada and Alaska. In late February and into March, you can see them closer to home in our own park woods and waters.

Winter is a colorful season for woodpeckers in Annandale. Those of us at a certain age can remember Woody Woodpecker’s signature quote and his subsequent maniacal laughter. However, when folks call us at Hidden Oaks Nature Center to ask about woodpeckers knocking on their houses, they generally aren’t laughing.

Woodpeckers knock for a variety of reasons, not the least of which is communication and territorial establishment. That’s why sometimes they knock on metal drainpipes and gutters to the puzzlement of our patrons. “But it’s not wood!” they contest. Woodpeckers though, know that drainpipes, like many hollow logs and snags in the forest, are amplifiers. Once they learn through experience how raucously they can knock, they return to the source. That’s how woodpeckers tell others of their presence and/or perhaps availability. That’s the good news they want to broadcast.

However, they might be broadcasting bad news to you. If they’re knocking on your wooden eaves or fascia boards they might be hunting insects that are already rooting around in there, potential headaches for homeowners.

And about those headaches — why don’t woodpeckers suffer from them? It turns out that, unlike heavy-metal millennials in a mosh pit, a woodpecker’s head is designed for head-banging. They can knock up to 22 times per second, and their tongues wrap all the way around the backs of their heads to provide excellent cushioning for their brains. This enables woodpeckers to withstand decelerations (knocking and its after-effects) at more than 100 times the impact than can humans. In fact, woodpeckers’ shock absorption qualities were intensely studied to design cases for flight recorders in airplanes.

That same super-long tongue is the scourge of insects everywhere, which wrongly think they’re safe hiding in deep holes of logs and standing dead trees or buried in the wood siding of your house.

Woodpeckers use their excavating skills to hollow out burrows, which are often used year-round as homes. Sometimes they’ll use existing holes, but some individual birds like to create their own nesting cavity each year. Different strokes for different species.

Hairy woodpecker

At Hidden Oaks right now, there’s potential for you to see downy, hairy, red-bellied, northern flickers and, during really cold weather, yellow-bellied sapsuckers at the suet feeders. You might also spy the much-larger pileated woodpecker with the prominent comb often thought of in connection to the aforementioned Woody Woodpecker. Cartoonist Walter Lantz, however, noted that the acorn woodpecker from the west was the actual inspiration for his ideas in the 1940s.

Woodpeckers breed in the late winter/early spring, but the pairing-off and courtship often starts in winter. During this time certain species get their brightest coloration to be more attractive to potential mates. This effect makes woodpeckers brilliant and vivid contrasts to the backdrop of winter’s bleakest, gray months.

Red-bellied woodpecker

Do you want to see woodpeckers in your backyard this winter? Suet feeders are the best way. Fill them with commercially-sold suet bricks, or just fill them with raw beef fat purchased from or donated by your local butcher.

Hidden Oaks Nature Center keeps suet and fat feeders out during the winter so our patrons can view these beautiful creatures on the fly. Come see for yourself.